Adjustable cramp for securing concrete shuttering or centering



May 11, 1934. H. o. MCKEOWN ADJUSTABLE CRAMP FOR SECURING CONCRETE SHUTTERING OR CENTERING Filed June 1, 1932 Patented May 1, 1934 ADJUSTABLE CRAMIP FOR SECURING CON- CRETE SHUTTERING OR CENTERING Herbert Oliver McKeown, Durban, Natal, Union of South Africa Application June 1, 1932, Serial No. 614,763. In the Unlon of South Africa September 23, 1931 10 Claims.

This invention relates to cramps for temporarily securing shuttering or centering in position while concrete is being placed, and until it has set.

It has hitherto been proposed to support concrete shuttering both internally and externally by means of a cramping device comprising a slotted sleeve housing a rotatable rod having a right and left hand screw thread at opposite ends respectively, an outer cramp member screwed on each end of the rod and passing through the slot in the sleeve, and an inner cramp member adjustably secured on the sleeve by means of a set screw adjacent each outer cramp member, the arrangement being such that oppositely disposed shuttering may be secured between the corresponmng inner and outer cramp members after the outer cramp members have been moved the required distance apart by rotation of the rod.

The improved cramp according to the present invention comprises a cranked or handled rod, a cramp member shaped to accommodate a shutter stiffening member and screw threaded on the end of the rod remote from the handle or crank, another cramp member also shaped to accommodate a shutter stifiening member and slidably mounted on the rod adjacent the handle or crank, and means for limiting the outward movement of the latter cramp member.

The improved cramp besides being conveniently fixed in position and readily removable after the settling of the concrete, is adjustable for various thicknesses of walls, columns, beams and the like.

In carrying the invention into effect the two cramp members are preferably forged or bent from a fiat steel bar and are mounted on the cranked and screwed rod which is adapted to draw them together when the handle or crank is rotated in one direction, and to cause them to recede from one another when said handle or crank is rotated in the opposite direction.

The cramp members are each bent to form the four sides of a square or rectangle with one side almost completely removed and leaving a substantial gap. When the cramp members are assembled on the cranked bar or rod the gapped sides are vertically disposed so that the gaps face inwards while the bar or rod passes through the outward facing or rear side or end adjacent its junction with the lower side, while the remaining short portion of the gapped side is provided with a hole or slot through which passes the said cranked bar or rod, that is, the said bar passes through the outward facing or rear side adjacent to and parallel with the lower side and through 55 the hole or slot in the short portion. The top side is preferably provided with a clamping screw.

The rear side of the cramp member remote from the handled or cranked bar or rod is screw threaded onto the latter, while the cramp member adjacent the cranked or handled end is provided with clearance holes and is free to slide along the bar. The portion of said bar adjacent the cranked end is threaded and carries two handled locking nuts for purposes of adjusting the relative position of the sliding chuck member at that end.

In a modification of the invention the threaded portion adjacent the cranked or handled end of the rod or bar is dispensed with and in place of the handled locking nuts a fixed collar is provided. In this case all the adjustment of the cramp members relating to one another is obtained from the screwed end of the rod or bar. Modifications in the construction of the chuck members comprise provision for preventing contact of the stifiening members with the screwed portions of the bar or rod.

To enable the invention to be more readily understood and carried into practice reference will now be made to the accompanying sheet of drawings wherein like references refer to like parts throughout all views.

In the drawing:

Fig. l is an elevation of the improved cramp showing the stiifening members and shuttering.

Fig. 2'is a plan view on Fig. 1.

Fig. 3 is an elevation of a modified construction of the invention.

Fig. 4 shows a modified construction of cramp member.

Fig. 5 shows a further modified construction of a cramp member.

Fig. 6 is an end elevation on Fig. 5.

Fig. 7 is a side elevation of a rod having an enlarged oval or cylindrical portion.

Figs. 8 and 9 are end elevational details of rods.

Referring to Figs. 1 and. 2 of the drawing, reference 1 denotes the bar or rod which is bent to form a crank handle at 2 and is screw threaded both at its end 12 and at 11 adjacent its handle end. The cramp member 3 is threaded onto the bar 1 as shown and a form stiffening member 14 is secured therein by means of the hand screw or stud 10. The cramp member 3 is tapped at 6 to co-operate with the threaded portion 12 while at 5 a clearance hole is provided. The cramp member 4 on the other hand is slidably mounted on the bar 1 and for this purpose clearance holes are provided at 7 and 8 while two hand locking nuts 9 provide adjustable means for limiting the outward movement of the cramp member 4 on the rod or bar 1. The cramp member 4 is also provided with a hand screw or stud to enable a stiffening member 13 to be secured therein.

In operation the cramp member 3 is first removed by unscrewing and the bar 1 passed through previously prepared coinciding holes in the shuttering or centering 31- when it is again screwed onto the portion 12 outside the centering. Both cramp members are now arranged to grip the form stiffening members as shown by" 13 and 14 in Fig. 1. Cramp member 4 is thereupon positioned by means of the hand lock nuts 9 and the handle 2 is then rotated until the correct width is obtained between the inside faces of the shuttering 31. If bulging or spreading should occur during the filling operation a turn or two of the handle will bring the shuttering into its correct position.

Fig. 3 shows a simplified modification of the invention in which the cramp members 16 and 17 are not provided with securing hand screws 10 while the screwed portion 11 is dispensed with and bar 15 has instead a collar 22 fixed thereto or formed integrally therewith at a point adjacent to the handle 23. The method of operation is obvious from an inspection of the drawing.

In Figs. 4, 5 and 6 are shown modified constructions for the cramp members. In both modifications shown the alteration lies in providing means to prevent contact between the bar or rod and the form stiffening members.

In Figs. 4 and '7 the short end 26 of the chuck member 24 is extended and bent round to a position parallel with the bottom portion as shown, and preferably welded or secured at 18. In t is manner the portion 25 forms a solid bearing for the form stiffening member and prevents its contacting with the screwed portion 30 when the securing screw 10 is tightened down on it. Figs. 5 and 6 show a further modification of cramp member 27 in which a small lug 28 is punched out from the rear end of the cramp member to form a ledge with which the top of short portion 29 forms means for supporting the form stiffening member and preventing contact between it and the screwed portion 30. These two modified forms of cramp members are particularly suitable in cases where the form stiffening members have become warped or otherwise deformed. In a further modification the unscrewed central portion of the rod may be of oval or other irregular section as shown at 31' in Fig. 9 to facilitateitsbeing loosened in the concrete, or it may be circular shape of slightly greater diameter than the screwed end as shown at 31" in Figs. 7 and 8. The length of the rods is only limited by the actual practical requirements.

What I claim is:-

1. An adjustable cramp for securing concrete shuttering or centering comprising a rod, a handle at one end thereof, a cramp member shaped to accommodate a shutter stifiening member and screw threaded on the end of the rod remote from the handle, another cramp member also shaped to accommodate a shutter stifiening member and slidably mounted on the rod adjacent the handle, and means for limiting the outward movement of the latter cramp member.

2. An adjustable cramp as claimed in claim 1',.

in which the central portion of the rod has an oval shape in cross section.

3. An adjustable cramp as claimed in claim 1, in which the central portion of the rod has a cylindrical shape of slightly greater diameter than the screw threaded end.

4. An adjustable cramp as claimed in claim 1, wherein clamping screws are mounted in the cramps for securing the stiffening members therein.

5. An adjustable cramp as claimed in claim 1, wherein the cramp member screw threaded on the rod has a hole tapped in its outer side to cooperate with the corresponding screwed portion of the rod, while the opposing cramp member is provided with clearance holes allowing of its free movement along the rod and wherein the limiting means include hand operated nuts for cooperating with a screwed portion of the bar adjacent the handle.

6. An adjustable cramp for securing concrete shuttering or centering comprising a rod, a handle at one end thereof, a cramp member shaped to accommodate a shutter stifiening member and screw threaded on the end of the rod remote from the handle, another cramp member also shaped to accommodate a shutter stiffening member and slidably mounted on the rod adjacent the handle, means for limiting the outward movement of the latter cramp member, and both cramp members having substantially a shape conforming to the periphery of a rectangle and having one side almost completely removed to provide a gap for accommodating the stifiening members.

7. An adjustable cramp as claimed in claim 6, wherein the gaps in the opposing cramp members, when the latter are assembled on the bar, face towards one another and the bar passes through both holes in the rear sides of the cramp members and the remaining portion of the gapped side in such manner that said bar lies parallel with and adjacent to the bottom side of the cramp members.

8. An adjustable cramp as claimed in claim 1, wherein the cramp member screw threaded on the rod is tapped in its outer side to cooperate with the corresponding screw threaded portion of the rod, while the opposing cramp member is free to slide on the rod and wherein the limiting means include a collar fixed on said rod adjacent the point at which the handle joins it, for the purpose described.

9. An improved adjustable cramp as claimed in claim 6, in which the cramp members are constructed in such a manner that the remaining portion of the gapped side extends to a position parallel with the bottom side and provides means to prevent contact of the stiffening members with the rod.

10. An improved adjustable cramp as claimed in claim 6, wherein a portion of the rear side of each cramp member extends inwardly and provides a ledge for the purpose of supporting the corresponding stiffening member and preventing its contacting with the rod.

HERBERT OLIVER MCKEOWN. 

